Rationale

The prevalence of X-ray spectrometric methods to measure coating thickness. B568 currently covers the use of X-ray spectrometric to measure coating thickness. However, this method is also used to determine chemical composition of the coatings. There is no standard that currently addresses issues of X-ray spectrometric. A standard is needed to ensure methods that ensure an acceptable degree of accuracy for alloy composition measurements. Thickness measurements utilizing X-ray spectrometry are detailed in ASTM B568. However, there are no ASTM test methods that address chemical composition determinations using X-ray spectrometry. This revision incorporates the method into API standard.